Assembly lines are used to mass assemble parts into a product such as a vehicle. Assembly lines are configured so as to sequentially and logically assemble the product from preassembled parts or raw material. It is common knowledge to establish an assembly line with a plurality of workstations. Each workstation performs a specific task that progressively assembles the finished product. Thus each workstation is tooled to accomplish its assigned task. As each workstation completes its assigned task, the part is transferred downstream the assembly line to the next workstation by a transfer system, such as a rail or a conveyor.
The workstation tools are usually monitored and controlled by a programmable controller (PC). The PC controls and detects the functions and operations of each tool so as to determine whether or not that workstation has properly completed its assigned task.
Disruptions in assembly lines can lead to unwanted expense in lost time and labor. Disruptions may result from a process abnormality, meaning a tool malfunction, improper tool performance, or an assembly worker, also referenced herein as an operator, has not properly performed a task. In such an event, the PC may stop and prevent an improperly assembled part from advancing downstream. Thus the process abnormality or the improperly assembled part can cause a disruption in the manufacturing process which in turn causes economic loss to the manufacturer.
With reference to FIG. 6, the current method for assembly line quality control is provided. The assembly line includes a stop which prevents the assembly line from advancing a part downstream. The stop may be actuated manually or automatically. The assembly line also includes an override which bypasses the stop and allows the assembly line to continue to advance parts downstream. However, in such cases the override disables all of the tools at the workstation where the process abnormality has occurred. Thus properly functioning tools are prevented from performing. Further, current systems do not capture the identification of the person who actuated the override. Lastly, current systems do not feed information relating to tool malfunction downstream the assembly line to ensure that defective parts are repaired.
Accordingly it is desirable to have a system which allows a part to advance along the manufacturing station in certain instances so as to minimize assembly line disruptions. However, it is also important and desirable to be able to identify the reasons why the part was not manufactured properly so that the error can be corrected later and also to identify the person who allowed the part to advance so as to be able to question the person and determine the reasons why. Further, it is also desirable to maintain a record of such occurrences so as to identify commonly recurring problems and provide corrective measures to prevent those problems from recurring.